The interactions of cell surface membrane components play crucial roles in transmitting extracellular signals to a cell in normal physiology, and in disease-conditions. In particular, many types of cell surface receptors undergo dimerization or oligomerization in connection with the transduction of an extracellular event or signal, e.g. ligand-receptor binding, into a cellular response, such as proliferation, increased or decreased gene expression, or the like, e.g. George et al, Nature Reviews Drug Discovery, 1: 808–820 (2002); Mellado et al, Ann. Rev. Immunol., 19: 397–421 (2001); Schlessinger, Cell, 103: 211–225 (2000); Yarden, Eur. J. Cancer, 37: S3–S8 (2001). The role of such signal transduction events in diseases, such as cancer, has been the object of intense research and has led to the development of several new drugs and drug candidates, e.g. Herbst and Shin, Cancer, 94: 1593–1611 (2002); Yarden and Sliwkowski, Nature Reviews Molecular Cell Biology, 2: 127–137 (2001).
A wide variety of techniques have been used to study dimerization and oligomerization of cell surface receptors, including immunoprecipitation, chemical cross-linking, bioluminescence resonance energy transfer (BRET), fluorescence resonance energy transfer (FRET), and the like, e.g. Price et al, Methods in Molecular Biology, 218: 255–267 (2003); McVey et al, J. Biol. Chem., 17: 14092–14099 (2001); Salim et al, J. Biol. Chem., 277: 15482–15485 (2002); Angers et al, Proc. Natl. Acad. Sci., 97: 3684–3689 (2000). Unfortunately, despite the importance of receptor dimerization and oligomerization in signal transduction processes, the techniques for measuring such interactions are difficult to apply, lack flexibility, and lack sensitivity. The lack of a convenient and sensitive technique for analyzing the oligomerization of cell surface molecules has greatly increased the difficulty of developing new therapeutics or diagnostic methods based on such phenomena.
In view of the above, the availability of a convenient, sensitive, and cost effective technique for detecting or measuring the dimerization or oligomerization of cell surface analytes would advance the art in many fields where such measurements are becoming increasingly important, including life science research, medical research and diagnostics, drug discovery, and the like.